Question

A boy has been diagnosed with ADA-deficiency. Suggest any one possible treatment.

Answer 1

Adenosine deaminase deficiency is caused by a defective enzyme, adenosine deaminase (ADA), necessary for the breakdown of purines. Lack of ADA causes accumulation of dATP. This metabolite will inhibit the activity of ribonucleotide reductase, the enzyme that reduces ribonucleotides to generate deoxyribonucleotides. Without functional ribonucleotide reductase, lymphocyte proliferation is inhibited and the immune system is compromised. It can be treated by gene therapy an alternative to the bone marrow transplant. Transduction of the missing gene of ADA to the isolated hematopoietic stem cells using viral vectors. These cells then injected back into the body and began to express a normal enzyme. This, augmented by weekly injections of ADA, corrected the deficiency. However, the concurrent treatment of ADA injections may impair the success of gene therapy, since transduced cells will have no selective advantage to proliferate if untransduced cells can survive in the presence of the injected ADA.